# Add Column source_mode
ALTER TABLE `tblpayoutrecords` ADD `source_mode` ENUM('wepay','tilled','other') NULL DEFAULT 'other' 
    AFTER `source_merchant_id`;

# Modify Existing source_mode based on source_merchant_id
UPDATE `tblpayoutrecords` SET `source_mode` = 
    CASE 
        WHEN `source_merchant_id` LIKE 'acct_%' 
            THEN 'tilled' 
            ELSE 'wepay' 
    END;